Mining gold or like metal



(No Modal.)

H. FRASCH. MINING GOLD 0R LIKE METAL.

M0. 565,342. Patented Aug. 4, 1896.

WMC @JMC UNTTED STATES PATENT OFFICE.

HERMAN FRAscH, orcLEvELAND, oHIo.

MIN-mc coLo R LIKE METAL.

SPECIFICATION forming part of Letters Patent-No. 565,342, dated.` August 4, 1896.

C Application filed August l 7, 1 89 5.

T 0 all whom, it may concern: l Be it known that I, HERMAN FRAscH, a citi- 'zen ot' the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio', have invented certain new and useful Improvements in Mining Gold or Like Metal; and I do declare the following to be a full, clear, `and exact description of the invention. This invention relates more particularly to the recovery of gold from placer deposits which eit-her contain the gold in too small quantity for Working by the methods heretofore known or used, or which from lack of Water or pec'uliarity of location are not Work- Vable, at least profitably, bysaid prior methods.. It may, however, be applied to the recovery of gold from other porous or permeable deposits and to the recovery from such deposits of analogous metal, (silver.1 or platinum, for example,) and it is generally to be understood that each of the improvements constituting the said invention is intended to be secured for all the uses to which it may l be applicable.

In accordance with said invention a reagent, which converts the naturally insoluble gold or analogous metal into a compound or compounds soluble in water, is introduced into the porous or permeable auriferous orl analogously metalliferous earth, which is generall y sand or gravel, as it lies in its natural bed in the ground. Theaqueous solution of l gold or the like, formed by the aid of such reagent, is removed by any known or suitable means for conveying liquids, such as pumping or the like, including drainage, if the sitnation admit of it, and the gold or like metal is recoveredy from the solution by known or suitable means for recovering metal from solution, such as chemical precipitation, electrical deposition, or the like. Where the earth contains other like metal as Well as gold, these may be mined together by using a reagent which converts both into soluble compounds, or they can be mined separatelyby `using in succession reagents oirwhichreachA renders one of the metals soluble.

In the introduction -of the reagent which renders the gold or like metal soluble hydrostatic columns, pumps, or other pressure- Serial No. 559,672. (No model.)

applying means may be used to force the reagent into the earth, or reliance may be had, when the earth is suiiciently permeable, upon gravity alone. Practically the use of pressure is important andis specially claimed.

The reagent employed may be any known or suitable substance or combination of substances for forming soluble compounds with gold or like metal, such as chlorin and bromine for gold, the alkaline hyposulites for silver, and potassium cyanid for gold or silver, or both. Chlorin maybe advantageously used for platinum. Thisis often present with gold and can be mined with it by means of chlorin. These are given as illustrations. Other reagents maybe used. In using a combination of substances they may be used in admiXt-ure or in succession. An example of the successive use of substances would be the formation of silver chlorid by the introduction of chlorin and the making of this silver chlorid soluble in Water by means of sodium hyposulte.

It is most advantageous to use the reagentin aqueous solution, such solution being introduced into the auriferous or argentiferous or platiniferous earth in its natural bed in the ground and allowed to remain fora suitable time in contact therewith in percolatin g or while standing. The more or less strong solution of gold (or silver or platinum, or two or more of them) is then withdrawn.

The gold and like metals are, as a general thing, distributed unequally through placer deposits, the Working of which is more particularly the object-of the present invention. The gold, forexample, in sucli'deposits is, as a rule, mainly-or almost 'wholly in the lower part near the bed-rock. 'The reagent may be allowed to find its way to the metal through overlying or intermediate masses of earth, which are but slightly or not at vall auriferous or argentiferous or platiniferous; but it is an improvement to drive a well, shaft, ditch, or tunnel to or near the4 auriferous or argentiferous or platinifero'us portion of the mass and to introduce the reagent more directly thereto by means of such well, shaft, ditch, or tunnel. Practically Wellsor shafts would be sunk or driven (at least in most IOO cases) down to the bed of the rock, so that the pit of the well or shaft is in the metalliferous earth.

Sometimes it may be desired to mine the metal from auriferous or like earth, which is so liooded with water-as to interfere with the penetration or operation of the reagent. In such cases it may be possible to drain off the excess of water; butif this is not practicable, or it be preferred not to do so, a chemical solution of a suitably high specific gravity may be introduced under the water-carrying earth and be made to displace the water,

'- so that the reagent may enter and act upon the gold or like metal. A proper specific gravity of the chemical solution may be obtained (at least in some cases) by the 'use of a Sufficient quantity of reagent; but where this is Itoo expensive or for any reason is not desirable it may be secured by additions of other substances, the most convenient substance being common salt, (sodium chlorid.)

As already indicated, the reagent may act upon the gold or like metal in percolating through the ground or While standing therein. To collect'the metallic solution formed in percolation, intercepting receptacles are provided at a suitable depth having openings or outlets for giving access thereto. These receptacles may be simply the pits at the botrom of wells sunkv into the mine, or they may be formed by open or covered ditches, or they may be formed in whole or in part by artiicial walls, (vertical or horizontah) or they may be formed in other like ways. To provide for the reagent standing in contact with the gold or like metal, walls may be built in the mine, so as by themselves or in connection with the natural rock to form charnbers or basins inclosing the auriferous or argentiferous or platiniferous earth, access for removal of the solution of gold or like m etal bein ggiven by shafts or other openings.

These could serve also to introduce the chemical solution, which might,however,be allowed to percolate into the basin. In some cases artificial basin-forming walls may not be necessary, the reagent when introduced into the ground standing suiiiciently inconsequence of the nature or natural surroundings of the auriferous or like earth. In such case (as also vin the case of an 'artificially-formed basin) the same pipe, well, shaft, or tunnel may serve to introduce the reagent which renders soluble the gold or like metal and to remove the solution of v`gold or like metal. The reagent can bel applied to the same earth and the metallic solution removed therefrom repeatedly, as often, in fact, as a yield is obtained.

The mine to be treated in accordance with this invention is generally a deposit in an excavation in solid rock, (such as the bed of an ancient river,) and the most advantageous treatment (itself a special improvement) is to build one or more walls at intervals across the excavation or valley (they extending from the bed-rock upward to the surface or to any desired distance above or below the same) and to sink or drive a number of Wells or shafts at intervals in the parcels of ground above such walls.

. As already stated, it is an advantage and a special improvement to force the reagent into the earth. It is also an advantage to exhaust the solution of gold or like met-al from the earth by the aid of a vacuum or diminution of pressure in the earth around the well-pit below the level of such solution.

In order to enable those skilled in the art better to understand and carry out the invention, the following particular examples are given by way of illustration of certain modes of practicing the invention, reference being had to t-he accompanying drawings, which form part of this specification, and in which- Figures l and 2 are diagrams, respectively in plan and longitudinal section, of a mine in an ancient river-bed provided with artiicial basin-forming walls and with wells or shafts whose lpits constitute intercepting 'recep- IOC troducing or reagent-removing pipe on a larger scale than that of the other figures and in section.

Let it be assumed that the mine consists of auriferous sand and gravel A and overlying earth A, Which contains little or no gold, deposited in the bed of an ancient river between thebanks B, and that `such deposit averages twenty feet in depth and two hundred feet in width, the dip of the bed-rock C being ifty feet to the mile. These figures substantially represent an actual case. The diagrams, it will be understood, are not intended to preserve the proportion to one another of the different dimensions. It will, of course, also b'e understood that the dimensions and other circumstances and their relations to one another are variable in reality. At intervals of about half a mile or at greater or less interrock and provided with suitable pipes or cas ings or pipes and casings.

IIO

In Fig. 5 the well is shown provided with a pipe 2, which fits closely the bore of the well, so that a vacuum can be maintained in the well-pit, the surrounding earth forming a packing. The pipe is shown as resting on the bed-,rock and is provided with perforations near its lower end.` Preferably the pipe 2 is of iron, coated internally and externally with lead, although it may be of wood or lead, or any material of suitable strength able to resist or protected against corrosion by the reagent. Near its upper end the pipe 2 is con'- nected through anon-corrodible pump 3 with a lead-lined or other non-corrodible tank 4, which latter is provided with a non-corrodible pipe-line 5. The pump 3 removes the metallic solution from the well and delivers it into the tank 4, to be thence discharged by the pipe 5. The tank 4 might also serve to receive the chemical reagent and the pump 3 to withdraw it therefrom through a suitable connection with the bottom of the tank and force it through the pipe 2 into the metalliferous earth, A or the reagent may be introduced from any suitable source through the pipe 2 independent of the pump, or part may be run in directly through the pipe 2 and part be forced down by the pump 3.

In Fig. 6 the well is provided, like an oilwell, with a casing 2 to inclose the pipe 2, and an underground pump (not represented) whose sucker-rod 6 is shown connected with one end of a walking-beam 7, the opposite end being provided with a chain or rope 8, that leads to an engine (not shown) for reciprocating it and the sucker-rod. The casing is perforated near the bottom. The pump raises the metallic solution and delivers' it through the pipe 2 into the tank 4, from which it may be discharged by the pipe 5. For introducing the reagent the pump with its pipe and packer could be removed and a pipe and packer inserted for introducing the reagent.

In Fig. 7 the tank 4 has its bottom and top both connected with the pipe 2, and a branched pipe 9, with a valve in each branch, leads to both the induction and discharge sides 0f an air-pump l0, so that air can be forced into the tank 4 or be exhausted therefrom, as the operatormay determine. A stopper 11 for closing the bottom opening when desired is indicated in dotted lines. By filling the tank 4 (through the pipe 5 or otherwise) and then compressing air into it by t-he pump l0 the reagent may be. forced down the pipe 2, the stopper ll being raised and the pipe 5 closed and the pipe 9 being in communication with the compression side of the pump 10., By shutting the stopper ll and putting the pipe 9 in communication with induction side of the air-pump a vacuum can be made in the tank4 and the metallic solution made to rise through the pipe 2 and Iiow into the tank 4. By opening the pipe 5 (the stopper 11 being shut) and causing the pump 10 to force air into tank 4 pipe 5.

'in any other suitable way.

The Wells of Figs. 1, 2, and 3 may each be equipped like the wells of Figs. 5, 6, or 7, or

ments of Figs. 5 and 7 are intended for shallow wells, as they raise the solution of gold or like metal by vacuum; but the arrangement of Fig. 6 could be used with wells of any depth. A force-pump could also be used at the bottom of shallow wells. Other forms of pumping or lifting apparatus could be'used instead of piston-pumps. When the wells are chlorid of lime (bleaching-powder) in water and adding enough sulfuric acid to liberate the chlorin. The use of about four pounds of the chlorid of lime to a ton of Water is recommended. The solution can be used at It iS in- 9o once, or be first allowed to settle. troduced into the auriferous earth' through one or, more of the wells, and may beintroduced in sufficient quantity to soak the auriferous earth in the entire basin formed by a wall D. To do this, the height of the wall D (on the basis of a dip of fifty feet to the mile and half a mile between Walls) would have to be twenty-five feet plus the depth of the auriferous deposit at the upper end ofthe basin.

If the walls were only a quarter of a mile roo apart, their height might be twelve and onehalf feet less with the same dip. Itis not necessary, however, to ill the whole basin. The solution may be introduced at one orm more of the wells and be allowed or forced to percolate to others, from which it could be pumped out. A continuous ow might, in fact, thus be maintained.vr If the overlying earthA' is suiciently impervious, the solution might be made +o ilow out of a well by pres- 1 Io sure of the solution inthe stratum A. The solution might simply be forced into the sand or gravel about a well, left there for a suitable time, and then pumped out through the same shaft and even the same pipe, the oper- 1 I 5 ation being repeated as often as desired until the yield ceases.

It is generally recommended to introduce the solution at the highest well and remove it at the lowest, or at one of the intermediate 12o ones if it be suciently charged with gold.

The solution may remain in contact with the gold-'carrying deposits for hours, days,

weeks, months, or even years. Veak solutions may therefore be used, and the extraction canbe continued until practical exhaustion of the gold. Any depth can be worked. As placer deposits do not ordinarily contain sulfids, nor other'substances on which the chloriu would waste itself, loss from this 13o cause would usually not have to be taken into account. In some cases where organic matter exists a solution of cyanid of potassium can be used more advantageously. It

The arrange- 7o Vith drive -pipes or hydraulic So the wen if preferred.

can be handled With iron pumps and iron tanks. Solutions of two-tenths of one per cent. (or even one-tenth) Will answer. In using chlorin for gold, if there be silver in the deposit, the ehlorid of silver formed thereby could be recovered by means of hyposulfite solution. If there be platinum, it would be 'recovered With the gold by the chlorin.

XVhen a sufficiently-rapid percolation is obtained thereby, the solution. may simply be run into the Wells; but When desired it can be forced by pressure in the wells to penetrate the surrounding earth.

The hillside mine in Fig. 4 is provided at an elevated point yvith a reagent-introducing opening F in the auriferous or like earth A and overlying deposit A in the form of a ditch and at a lower point with a cement Wall D from the bed-rock C to and above the top of the ground at that point. In the ground above, the Wall D and in proximity thereto is a Well E and beloWit a ditch G, .Which extends to bed-rock C. On introducing the reagent in aqueous solution into the ditch F by pumps, buckets, conduits or other like means, said solution flows down the hillside, percolating through the auriferous or like earth A, converting the gold or like metal therein into a compound soluble in Water and dissolving the same. The Wall D intercepts the metallic solution so formed, which can be removed through the well E by the appliances of Figs.

'5, 6, and '7, or by other like means. In some cases gravity might force it to rise through the Well-pipe; also, it might be drained off through an opening at or near the bottom of the Wall D into the ditch G, from Which it might be lifted out by pumps or buckets or other liquid-lifting appliances; also, the solution might be carried (if the situation permit) into a storage or treating vat at a lower level by drainage directly fromv the receptacle or basin above the Wall D or from the ditch G. If desired, the solution can be removed as fast as it percolat-es into the receptacle formed ,by the Wall D, or it can be allowed to collect therein and to stand in contact with the gold or like metal before it is removed. Further, the -Wall D and Well E might be dispensed withand the solution be intercepted by the ditch Gr, to be' removed by pumping, drainage; or otherwise. Of course also the Wall D might be-used Without the ditch and Without other suitable outlet be provided. l

'After the gold solution has been obtained, the gold is recovered therefrom as may be Electrical deposition is considered the most advantageous mode, thechlorin solution being regenerated while the gold is Y deposited. It is unnecessary to go into the details of an electric deposition, as those skilled in such matters will understand how to ap-y So, also, if chemical precipitation be preferred for the recovery those skilled in the,

ply it.

art will lunderstand how to apply it Without further instructions. The regenerated solu-A lution of chlorin could be introduced again into the auriferous earth.

If an analogous metal, like silver or platinum, is to be mined instead of or along with gold, the preceding description Will suffice for vplatiniterous earth in its natural bed in the ground a reagent which converts such metal into a compound-soluble in Water, and removing the aqueous solution of gold or like metal formed by the aid of such reagent; substantially as described.

2. The process of mining gold, or analogous meta-l such as silver or platinum, by introduc-y ing into the auriferous or argentiferous or platiniferous earth in its natural bed in lthe ground a reagent Which converts such metal into a compound soluble in Water, removing the aqueous solution of gold or like metal formed by the aid of such reagent, and recovering t-he metal therefrom; substantially as described.

The process of mining gold or analogous met-al such as silver or platinum, by forcing under pressure into the auriferous or argentiferous or platiniferous earth in its natural bed in the ground a reagent which converts said metal into a compound soluble in Water,

and removing the aqueous solution of gold or like metal formed by the aid of such reagent; substantially as described.

4. The process of mining gold, or analogous metal such as silver or platinum, by introducing into the auriferous or argentiferous or platiniferous earth in its natural bed in the ground an aqueous solution of a reagent which converts such metal into a compound soluble in Water, and removing the aqueous solution of gold or like lnetal formed by the aid of such reagent; substantially as described. l

5. The process of mining gold, or analogous metal such as silveror platinum, by driving a Well, shaft or opening in the ground through overlying 'or intermediate masses to, into, or through the aurit'erous or argentiferous or platiniferous earth or its vicinity, introducing into such earth through such Well, shaft or opening, a reagent which converts such metal into a compound soluble in Water, and removing the aqueous solution of gold or like metal formed by the aid of such reagent substantially as described.

G. The process of mining gold, or analogous metal such as silver or platinum, by introduc- IIO ing into the auriferous or argentiferous or platiniferous earth in its natural bed in the ground an aqueous solution of a reagent which converts such metal into a compound soluble in Water, such solution being of a high speciiic gravity and so introduced as to displace Water which the said earth may carry, and removing the aqueous solution of gold or like metal formed by the aid of such reagent; substantially as described.

7. The process of mining gold, or analogous y metal'such'as silver or platinum, byintroduc- -nictal such as silver or platinum, by driving a well, shaft or opening in the ground through overlying or intermediate masses to, into, or through the auriferous or argentiferous or kplatiniferous earth or its vicinity, introducing into such earth Jthrough such Well, shaft or opening, a reagent which converts such meta-l into a' compound soluble in Water, causing such reagent in solution to percolate through such earth, and removing the solution of gold or like metal from one or more intercepting receptacles through'other Wells, shafts or openings; substantially as described.

9. The process of mining gold, or analogous metal such as silver or platinum, by inclosing the auriferous'or argentiferous or platiniferous earth iu its natural bed in the ground in one or more artificially-formed basins, in-

troducing into such basin a reagentpwhich converts such metal into a compound soluble in Water, and .removing the aqueous solution of gold or like metalv formed by the aid of such reagent; substantially as described.

l0. The process of mining gold,or analogous metal such as silver or platinum by inclosing the auriferous or argentiferous or platiniferous earth in its natural bed in the ground in one or more artificially-formed basins, driving one or more wells, shafts or openings into the earth in such basins or the' vicinity.

thereof, introducing into the basins a reagent which converts such metal into a compound soluble in Water, and removing the aqueous solution of goldor'like metal formed by the aid of such reagent; substantially 'as described.

11. -The process of mining gold or platinum, by introducing a solution of chlorin into the vauriferous or platiniferous earth in its natural bed in the ground, and removing the chlorid-of-gold or platinum solution formed thereby; substantially as described.

l2. The process of mining gold orplatinum,

by introducing a solution of chlorin into the auriferous or platiniferous eart-h in its natural bed in the ground, removing the chloridof-gold` or platinum solution formed thereby, and recovering the gold or platinum by electrical deposit; substantially as described.

13. The process of mining gold or platinum by introducing a solution of chlorin into the auriferous or platiniferous earth in its natural bed in the ground, removing the chloridoffgold or platinum solution formed thereby, recovering the gold or platinum and regenerating the chlorin solution by electrical deposit, and introducing such regenerated solution into the ground for acting again upon the gold or platinum to effect its removal in solution; substantially as described.

' ll. A mine of gold, or analogous metal such as silver or platinum, composed of one or more Wells, shafts or openings in the ground to, into, or through the permeable auriferous or argentiferous or platiniferous earth or the vicinity thereof, and provided with means, such as pumping mafgiinery or the like, for intro ducing or forcing a fluid reagent into the said earth, and for removing or exhausting and removing the gold or silver or platinum solution; substantially as described.

. l5. Amine of gold, or analogous metal such as silver or platinum, composed of a basin With an artificially-formed Wall or Walls iiiclosing auriferous or argentiferous or platiniferous earth in its natural bed in the ground, with one or more wells, shafts oi" openings into said basin, and provided with means,

IOO

such as pumping machinery or the like, for

Pas silver or platinum, composed ofV one `or more reagent introducing Wells, shafts or openings in the ground on one side of the permeable auriferous or argentiferous or plat; niierous earth and on the other side there Aone` or more intercept-ing receptacles having openings to give access to suchl receptacles, said mine being further provided with means .for introducing the chemie/al reagent and removing the solution o'f gold or analogous metal; substantially as described.-

17. A mine of gold, or analogous metal such as silver or platinum composed of a deposit of auriferous or like earth in a natural excavation like a river-bed, and provided with one or more basin-forming Wallscacross the excavation or valley anda/lso with one or more wells or shafts ,in the parcels of ground above such Walls; substantially as described.

V18. The.' process .of mining gold, or analogous metal such as silver or platinum, by introducing into a natural body of permeable auriferous or argentiferon's or platiniferous IIC earth in its natural bed in the ground a reaqueous solution, and recovering the metal agent which Converts such :metal into a oomtherefrom; substantially as described. Io pound soluble in Water, so that the said earth In testimony whereof I aX my signature is permeated by said reagent percolating in presence of two Witnesses. through or standing in the said earth and the HERMAN FRASCH. particles of gold i distributed through said Vitnesses:

earth are thus exposed to said reagent, re- F. W. LOTHMAN,4

moving the compound thus formed in dilute Y N. J. VORLEY. 

